Conventionally, as an electronic device unit for constructing a system where the electronic device units are attached to a DIN (Deutsche Industrie Normen)-standard rail and coupled with each other in a lateral direction, there is an electronic device unit having a casing configured by a box-like case without a lid and a lid-like lock/unlock component having a slider mechanism.
The case is provided with an L-shaped coupling hook on an outer coupling surface, and the lock/unlock component is provided with a slider and an engagement hole. The coupling hook of the case of one of the electronic device units is inserted into the engagement hole of the lock/unlock component of the other electronic device unit, and the slider is moved to a lock position, thereby causing the slider located between the coupling hook and the engagement hole to function as a bolt. Further, by moving the slider to an unlock position, the slider is released from a space between the coupling hook and the engagement hole, and the electronic device units can be separated from each other.
In the conventional technique described above, for the sake of fixing the slider to the lock position, an arm is provided on the slider, and a stepped shape is formed on the case. At the time of sliding the slider to a lock position, the tip of the arm runs over the step of the case and drops down into a concave part, by which the slider is fixed at the lock position.
Patent Literature 1 also discloses a side-coupling type programmable controller unit where fitting positions between a click-stop protrusion of a lock slider and two click-stop concave parts of the electronic device unit body are changed so as to switch between lock and unlock.